Web winder control

ABSTRACT

Apparatus and method for controlling the operation of continuous web perforating and winding machines, especially of the type used to manufacture plastic bags and automatically wind the bags into small rolls for consumer use. The invention provides means of winding a specified number of bags into each roll and severing the perforated plastic web at a line of perforations at a position suitable for automatically transferring the leading end of the web to a winding spindle.

[ Jan. 1, 1974 United States Patent [191 Donnell, Jr.

FOREIGN PATENTS OR APPLICATIONS WEB WINDER CONTROL Inventor Donneu, Neshanic, 12/1970 242/568 [73] Assignee: Egan Machinery Company,

Primary Examiner-George F. Mautz Somerville, NJ. Assistant ExaminerEdward J. McCarthy A: A. V p 19,72 torney David erner Appl. No.: 248,713

[22] Filed:

57 ABSTRACT Apparatus and method for controlling the operation of continuous web perforating and winding machines, especially of the type used to manufacture plastic bags and automatically wind the bags into small rolls for 6 WW5 ,3 w M fiw U mh4 52 "6 m m mmhm ""c .r uua nu nus L "f o m d Std Umn 1]] 2 8 555 [ll 83/369; 225/l04 consumer use. The invention provides means of winding a specified number of bags into each roll and severing the perforated plastic web at a line of perfora- [56] References Cited UNITED STATES PATENTS tions at a position suitable for automatically transferring the leading end of the web to a winding spindle.

242/56 R Pickering.......................... 83/369 x 4 Clams, l Drawmg Figure Willshaw..................

659 366 999 Ill 2 2 000 062 ,5 17] 3600 233 WEB WINDER CONTROL BACKGROUND OF THE INVENTION This invention relates to winders for use in winding flexible webs of paper, plastics and the like and in particular to the control systems and method of controlling of the same wherein a flying transfer winder winds rolls of perforated material.

Plastic bags such as used for trash can liners, refuse bags, sandwich bags and the like are manufactured by extruding the plastic through an annular die into a tube, inflating the tube and then collapsing the tube in a pair of nip rolls. This is the blown film method of making collapsed or lay-flat tubing and is well-known in the art. In a frequently used method to form bags, the layflat tubing is heat sealed in a narrow strip transversely across the web and at or about the same time is perforated by a serrated knife transversely across the web close to the seal while in line with the extrusion equipment or from wound mill rolls of tubing having been previously manufactured.

For consumer use, the resultant sealed and perforated web passes either to equipment which separates the bags and folds them so that they may be packaged, or to equipment which winds the web into small rolls each containing a specified number of bags which are then packaged. The rolls may be wound on cores, or in some cases coreless winding is preferred.

This invention concerns apparatus of the latter class wherein the web is wound into small rolls, either on cores or coreless on mandrels and specifically for providing means for winding a specified number of bags on each roll and transferring the web to a new core or mandrel at the correct time so that a successful fying transfer may be made.

The usual type of flying transfer winder having a knife to cut the moving web before transfer is not suitable for operation on sealed and perforated bag stock since it is not possible in practice to synchronize the knife operation with the perforations so that the cut will always be made on the line of perforations. If the cut is made other than on the line, a bag is wasted and the result is a partial bag at the end of one roll and the beginning of the next which is not only wasteful but also objectional to the purchaser. Applicant therefore prefers to use a modification of the method disclosed in Schultz US. Pat. No. 2,266,995 wherein the sealed and perforated web is torn apart at the perforations whilst the web is gripped by two sets of driven nip rolls, the downstream set having a greater peripheral speed than the upstream set.

To transfer the leading end of the separated web to the new core or mandrel, applicant prefers to use the transfer method disclosed in Hellemans U.S. Pats. No. 3,501,104 and 3,642,221 wherein an air stream is used to guide the leading end of the web around the new core or mandrel and start the new roll. Although the above are the preferred methods of severing and transferring the web, the present invention is not limited to use with the apparatus and methods of the aforementioned patents.

In order to operate successfully, it is necessary that a signal be given to the winder to initiate the transfer action when, first, the correct number of bags has been wound and, second, the line of perforations at which the severing of the web occurs is in the correct position for the transfer. It has been proposed that a detection device and accompanying counter device be mounted on the winder to detect and count the perforation lines on the web entering the winder. However, in practice it has been found that known detection devices that will detect a line of perforations in a moving web are expensive and unreliable in operation, especially as in the case of plastic bag stock wherethere may be two or more layers of material. Applicant has found that by use of a signal obtained from the perforating and sealing machine preceding the winder and appropriate counting devices, a reliable signal can be obtained to initiate the transfer at the correct instant. The apparatus of the inventionmay also be used in the same manner for web materials which have been perforated only.

It therefore is an object of the invention to provide a means of signaling apparatus for winding rolls from a web of material having transverse perforations in order that a specified amount of material may be wound on each roll.

A further object is to provide a signal that will allow flying transfers to be accomplished on a winder for the above material.

DRAWINGS The FIGURE shows a sectional side elevation of a flying transfer winder which incorporates the present invention.

Referring to the FIGURE, a continuously moving web of material W from a previous operation enters a perforating and sealing apparatus shown generally at 10. This disclosure will describe a typical plastic bagmaking operation wherein the web W is comprised of a plastic, such as polyethylene, which has been manufactured as a tube by the blown film process and enters the perforating and sealing apparatus as a flattened tube. The perforating and sealing apparatus may be of any known type in which a transverse line of perforations and an adjacent transverse heat seal are made at regular intervals on a continuously moving web, the distance between each line of perforations representing the length of each bag. It is only necessary for the purposes of this invention that a signal, preferably an elec trical impulse, is provided by the perforating and sealing machine at some predictable and consistent time during the perforating cycle which has a direct relationship to the time of perforation. This signal may be generated by various means well known in the art, for example by a limit switch operated! by the perforating mechanism or by a web length counter by which the perforating mechanism is actuated.

From the perforating and sealing apparatus, the perforated and sealed web passes around idler rolls 11 and 12 and through the nip of pull rolls l3 and 14, of which roll 14 is driven by conventional means, and thence into the winder, shown generally as 15.

Flying transfer winder 15 in the embodiment shown comprises three driven winding spindles 16, 17 and 18 all mounted on a turret 19 capable of rotation in the direction shown by the arrow. The drawing shows the winder at the position an instant before the flying transfer is made, where web W passes over idler roll 20, through the open nip formed by driven roll 21 and the new core 22 mounted on spindle M, then through the open nip of driven rolls 23 and 24 and then wound up as roll 25 on spindle 17. Rolls 21 and 23 are mounted on pivoted arms 26 whose position is controlled by actuating fluid cylinder 27 and stop fluid cylinder 28 while roll 24, which is preferably rubber covered, is mounted on pivoted arms 29 controlled by fluid cylinder 30. Roll 21 and the spindle 16 are driven at speeds corresponding substantially to the line speed of the web while rolls 23 and 24 are driven at speeds considerably higher than that corresponding to the web.

The control means of this invention provide a signal to the winder when the correct amount of bags has been wound in roll 25 and when a line of perforations is between the new core 22 and the rolls 23 and 24. At this time air is quickly exhausted from stop cylinder 28 and since actuating cylinder 27 is energized upwards, the roll 21 is lowered to contact the web on the new core and simultaneously the nip between rolls 23 and 24 is closed. Due to the differential in speed of the rolls, the web is torn apart at the line of perforations between the new core and the nip of rolls 23 and 24 and the leading end of the web is wrapped around the core by an air stream issuing from air chamber 31 and air shield 32 to start a new roll. Reference may be had to US. Pats. No. 3,501,l04 and 3,642,221 for details ofthe apparatus and operation of the air chamber and shield. However, it is important to the operation of this system that the tearing or severing of the web be accomplished immediately after the line of perforations passes through the nip of roll 21 and the new core in order that the leading end of the web may be directed around the core by the air stream.

The control system of this invention provides a precise signal to meet the above requirements. The signals from the perforator and sealer indicating when lines of perforations have been made are fed into preset bag counter 33. When counter 33 counts out, it resets itself to zero and at the same time resets the preset length counter 34 to zero. By means of pulse generator 35 suitably connected to driven pull roll 14, the length counter 34 then counts or measures the length of the web passing through the nip of rolls 13 and 14 and into the winder. The counter 34 has been preset to a count representing the actual length of the web path from the location of the perforation in the perforating machine at time of signal to the desired web tearing or severing point adjacent to the nip of the roll 21 and the new core. At count out, counter 34 provides a signal to initiate the web transfer as heretofore described and at this time the line of perforations will be in the correct position for severing the web.

The counters suitable for use in the practice of this invention may be, among others, of the electromechanical or electronic type, although for medium and high web speeds it is preferred that the length counter be electronic which can count faster than the electromechanical and thus will provide practical resolution for adjustment of perforation position. These counters count each electrical pulse received and when the count reaches a preset number, known as count out, an electrical signal is provided by the counter to some other component in the system and at the same time resets itself to zero count and commences counting again.

In an example, it may be assumed that it is desired to manufacture bags having a length of 36 inches, that 24 bags be wound on a roll and that the web path from the location of the line of perforations in the perforating machine at time of perforation to the web tearing or severing point on the winder is 240 inches. The bag counter 33 is preset at 24 and the length counter 34 at 240. The counter or other device on the perforator will provide a signal at 36 inch intervals at the time each line of perforations is made. These signals are fed to the bag counter 33 which will register one count, representing one bag, each time the perforator operates. When the bag counter reaches 24, it resets itself to zero and then starts to count over. At the same time it resets the length counter 34 to zero and this counter then measures the length of web entering the winder until it reaches 240 at which time the line of perforations has reached the correct position and the transfer is initiated.

It may be noted that the first roll wound will contain more than 24 bags; that is, the number counted plus those that were in the web between the perforator and the winder at the start, but all rolls thereafter will contain the correct number of 24.

There are three primary parameters of a perforating and winding system such as the disclosed, these being bag length, number of bags in a wound roll and web speed. It is an advantage of the control system of the present invention that each parameter is unaffected by any changes in any of the others. Since the web severing is always accomplished on the same line of perforations made at the time of count out of the counter 33, the bag length may be changed at the perforator at any time without effect on the winding operation or the settings of the bag and length counters. A change in the number of bags wound in a roll is accomplished by changing the preset count number of the bag counter with no other changes necessary. Changes in line speed, if small, require no adjustments but if large may require minor changes in the preset count of the length counter 34 to provide lead time for the closing of the nip of roll 21 and the winding spindle 16 or core 22 and the nip of rolls 23 and 24.

The control method and system of the present invention is not limited for use on the specific embodiments of perforator and sealer and flying transfer winder disclosed herein but may be used with other types of perforators, or perforators and sealers, and winders and in general may be utilized in any operation wherein a web is perforated at intervals and subsequently made into a plurality of continuously and automatically wound rolls.

1 claim:

1. Apparatus for controlling the operation of the combination of a perforating machine wherein a continuous web is transversely perforated at intervals and a flying transfer winder wherein the web is severed at a line of perforations and the leading end wrapped on a winding spindle, comprising:

perforator signal means to provide a first signal responsive to the time of perforation;

a first preset counter responsive to the first signal and providing a second signal at count out;

a second preset counter initiated by the second signal and responsive to the length of web advanced to the winder from the perforator and providing a third signal at count out; and

winder web severing means initiated by the third signal to sever the web in a position for making a flying transfer.

2. The apparatus of claim 1 wherein the length of web substantially equals the length of web measured from the location of the perforation in the perforating machine at the time of the first signal to the web severing position.

6 3. The method of controlling the operation of the winder from the perforator; combination of a perforating machine wherein a conintroducing said measurement as a count into the tinuous web is transversely perforated at intervals and second preset counter; a flying transfer winder wherein the web is severed at providing a third signal from. the second preset a line of perforations and the leading end wrapped on 5 counter at count out; and a winding spindle comprising: introducing the third signal to the winder to initiate providing a first signal from the perforator responsive the web severing at a position for making a flying to the time of perforation; transfer. introducing the first signal to a first preset counter; 4. The method of claim 3 wherein said measurement providing a second signal from the first preset 10 substantially equals the length of web measured from counter at count out; the location of the perforation in the perforating maintroducing the second signal to a second preset chine at the time of the first signal to the web severing counter to initiate counting; position. measuring the length of web advancing into the 

1. Apparatus for controlling the operation of the combination of a perforating machine wherein a continuous web is transversely perforated at intervals and a flying transfer winder wherein the web is severed at a line of perforations and the leading end wrapped on a winding spindle, comprising: perforator signal means to provide a first signal responsive to the time of perforation; a first preset counter responsive to the first signal and providing a second signal at count out; a second preset counter initiated by the second signal and responsive to the length of web advanced to the winder from the perforator and providing a third signal at count out; and winder web severing means initiated by the third signal to sever the web in a position for making a flying transfer.
 2. The apparatus of claim 1 wherein the length of web substantially equals the length of web measured from the location of the perforation in the perforating machine at the time of the first signal to the web severing position.
 3. The method of controlling the operation of the combination of a perforating machine wherein a continuous web is transversely perforated at intervals and a flying transfer winder wherein the web is severed at a line of perforations and the leading end wrapped on a winding spindle comprising: providing a first signal from the perforator responsive to the time of perforation; introducing the first signal to a first preset counter; providing a second signal from the first preset counter at count out; introducing the second signal to a second preset counter to initiate counting; measuring the length of web advancing into the winder from the perforator; introducing said measurement as a count into the second preset counter; providing a third signal from the second preset counter at count out; and introducing the third signal to the winder to initiate the web severing at a position for making a flying transfer.
 4. The method of claim 3 wherein said measurement substantially equals the length of web measured from the location of the perforation in the perforating machine at the time of the first signal to the web severing position. 